Breech-action for firearms



I. N. LEWIS. A

BREECH ACTION FOR FIREARMS. APPucATxpu FILED MAR. 24. m5.

1,344,91 1 Patented e 29, 1920.

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" IN 'TOR WITNESSES Swa /gym BY fi wflwv AT TURN EY UNITED STATESPATIENT OFFICE.

ISAAC NEWTON LEWIS, OF LONDON, ENGLAND.

BREECH-ACTION FUR FIREARMS.

Specification of Letters Patent.

Patented June 29, 1920.

Application filed March 24, 1915. Serial No. 16,599.

To all "whon'z. 712! m fly concern:

Be it known that 1, Isaac Nnw'roN LEWIS, a citizen of the United Statesof America, residing at 5 Adelphi Terrace, Strand, London, \V. 1.,England. have invented certain new and useful Improvements in BreechActions for Firearms, of which the following is a specification.

This invention relates to breech actions for auton'iatic andsemi-antomatic firearms, and the object of the present invention is topro- 'idc an improved breech action by which the breech may be openedand closed rapidly with a minimum of jar and shock and cruise qncnt wearof the moving parts.

The breech block of automatic lire-arms and especially those of the gasoperated type, is very commonly locked in firing position by having apartial rotary movement imparted to it by means ol the gas piston orother breech opening device. Now. it is clear that the time in which theunlocking operation may take place is very short and consequently thesudden overcoming of the inertia of a comparatively heavy breech blockontails a great strain on the operating parts and also exerts arestraining influence on the rapidity of lire.

The object of the present invention is to so ronstruct the breechmechanism that the main portion of the lJI'GQffl'l block does not haveto be turned to effect the locking and unlocking operations which areeffected by a relatively small and ligl'it locking piece capable ofrotation relatively to the main portion of the breech block. The lockingpiece is so designed that it may have its weight and hence its inertia,reduced to a minimum without in any way sacrificing the necessarystrength and reliability.

I preferably employ in connection with the improved breech block, afiring pin which is so arranged that its striking end cannot reach thecartridge cap until the breech block is properly locked in position.

Referring now to the accompanying drawings which show a. convenientembodiment of my improved breech mechanism applied to a small arm of thegas operated type:

Figure 1 is a longitudinal sectional View of the breech portion of therifle, showing the breech block in closed position;

Fig. 2 is a side View of the breech block with its locking nut removed.

Fig. 3 is a longitudinal sectional View of the breech block taken on theline 3-3 of hi g. el this view also showing the extractor [11 position;

Fig. at is an end View of the breech block;

Fig. 5 is a view or the breech block nut showing the inner end thereofand the lugs winch engage with those on the breech block proper;

Fig. 6 is a side view of the nut;

Fig. 7 is a. view of the outer end of the said nut.

Fig. 8 is a section thereof taken on the iine S-8 o'l Fig. 7.

Fig. 9 is a plan view on an enlarged scale of the cam piece which iscarried upon the gas operated piston rod.

Fig. 10 is a sectional View thereof taken on the line lU-1U of Fig. 9;

Fig. 11 is a section on an enlarged scale on the line 1l-ll of Fig. lthrough the receiver casing in. body piece. the magazine and allremovable parts being omitted, while Fig. 12 is a similar view taken onthe line li Jl2 of Fig. l. In the drawings, a is the barrel, 1) thewooden barrel support or casing, and c is the body piece in which thebreech block is adapted to reciprocate and which is proi ided withgrooves ll to receive lugs 10 on the breech block nut as hereafter morefully described.

The breech block is of peculiar character in that it is made up of twoparts, a long tubular part 4, and a short tubular part 5 at the rearwhich I will call the nut. The nut part 5 is connected to the tubularpart 4 by means of locking lugs 6 upon a spigot provided on the part 4,these lugs being arranged to engage behind corresponding lugs T in thenut part. In the example shown the looking or unlocking of the two parts4 and 5 is elfected by a relative rotation of about one sixth of arevolution.

The part 4 of the breech block is provided with a projection -8 which isadapted to run in aslot 9 in the body piece 0 of the arm; in this waythe part 4 cannot rotate but may only reciprocate in the body piece orreceiver. The not part 5 is provided with lugs 10 which are adapted torun (during the reciprocation of the breech block) in grooves 11provided in the body-piece or receiver of-the arm. When the'breech blockis in closed position as in Fig. 1, however, the nut part 5 is situatedin a space in the body piece or receiver of a diameter throughout asgreat as the depth of the grooves 11 (as shown by the dotted circle 11in Fig. 12) so that the nut can be ro tated to bring its locking lugs inor out of register with the said rooves, in order to effect unlocking orlOClI1g oi the breech block. In the construction shown about one twelfthof a rotation of the nut is required for looking or unlocking so thatthe nut is not, by such action, unlocked from the part 4 of the breechblock.

In order to effect the necessary rotation of the breech block nut forlocking and unlocking the same the cain piece 3 is provided. This campiece is detachably connected to a piston rod 3' by suitable lookinglugs and on its under side is provided with a cam slot 13 which isadapted to can gage a simple projecting piece 14 on the breech blocknut. When the brccch block is in closed position the projection 14 liesin the rear end of the cam slot, as will be understood from Fig. 1 andin this position the lugs ll) on the nut are out of register with thegrooves 11 in the body piece, or in other words the breech block islocked against backward movement. Upon the cam piece moving rearwardly,either by the action of the gases on the piston rod 3 or by pulling on ahandle 15 provided for the purpose, the cam slot 13 will cause the nutto rotate in a counter clockwise direction (looking toward the muzzle ofthe rifle) to a sufficient egtent to bring the lugs 10 into registerwith the grooves 11. The breech block is now unlocked and the continuedrearward movement of the cam piece will carry back the entire breechblock so as to open the breech.

It will be understood that the piston rod 3' is fitted with a piston atits forward end working in a suitable chamber having ac cess to thebarrel in the well known manner, so that when a cartridge has been firedsome of the discharge gases enter the chamber and drive back the piston.The stem of the handle 15 projects through a suitable slot in the sideof the casing 0' covering the rear portion of the receiver, so that thebreech may be opened by hand when de sired.

The breech block is provided with a suitable extractor 16 which fitsinto a recess 16' in the side of the breech block and has a. hook-likefree end 16" which engages the rim of a cartridge in the well knownmanner. It is made from spring steel and is sprung into place with itsrear edges 17 beneath the overhanging ledge 18' on the breech block, andwith the button 19 engaging the aperture 20 in the breech block.

The extractor is. provided on the right hand side of the breech blocklocking toward the muzzle of the rifle, and as the breech block isretracted the spent cartridge case is drawn out of the chamber by the extractor and when clear thereof is tipped out of the body of the riflethrough an opening 2H (see Fig. ll). To insure that this tip ping actionshall take place a pin is provided on the inner surface of the bodypiece opposite the opening which pin is accommodated in a slot 22 in thebreech block. hen the breech block has moved back far enough the base ofthe cartridge opposite the extractor is struck by the pin and the emptycase is forcibly thrown through the opening 20. The location of the pinis shown at 23 in dotted lines in Fig. 3.

in order to fire the cartridges a firing pin 2'21 is employed passingthrough a suitable aperture in the breech block and provided in thcEPn'." oi the nut with a plate 25 the lower portion oi which is shapedto run in the slot 26 in the body piccc r so that it can not rotate, Theforward side oi this plate 2? is provided with two projections 27.which, when the nut is in correctly locked position, he directly in rearof two depressions 28 in the rear side of the nut (see Fig. By thesemeans the firing pin can. only move forward sulliciently to fire thecartridgc if the breech block is locked, otherwise the forward movementof the pin will be arrested by the engagement of the projections on theplate with the rear face of the nut. hl oreover the action of rotatingthe nut to unlock the breech at once draws back the end of the firingpin from the cartridge in order to keep the firing pin in place it isprovided with a groove at 29 adapted to receive a split spring ring 30.This ring may be removed or placed in position when the nut is removedfrom the part 4 of the breech block as shown in Fig. 8, but when theparts are assembled the spigot piece on the part 4 will enter the hollowspace in the nut surrounding the split ring and prevent any chance ofits displacement.

The firing pin is operated to fire the car tridges by a striker 31extending upwardly through the slot 26 and carried upon a rod 32 whichextends into a. tube 83 in the stock 34., the striker being urgedforwardly by a spring 35 located behind it. The striker 31 is shown incocked position in Fig. 1 it be ing held in this position by the sear36. Upon pressing the trigger 37 the sear is depressed and the striker,now being free, moves forward under the action of the spring 35 until itstrikes the plate 25 on the firing pin 24. When the breech block movesrearwardly in the manner already described it carries with it thestriker 31, but upon the return of the breech block underthe action ofthe spring 35 and a spring 38 located around the piston rod 3 andoperating beemma tween the piston at the forward end thereof and astationary washer 39, the striker will be arrested by the sear 36 in thepositielf shown in Fig. 1 ready for firing the next shot when thetrigger is again pressed. As the details of the firing mechanism justdescribed form no part of the present invention further descriptionthereof is deemed unnecessary.

It is to be particularly observed that by employing a simple part on the"nut or locking piece 5, which part may be a mere projection andproviding the necessary meansior rotating the locking piece, viz the camgroove 13, upon the operating part of the breech mechanism, the nut orlooking piece can be made of only sufiicient dimensions to have therequisite strength and rigidity, whereas it the cam groove were to beprovided in the nut the dimensions of the latter and hence its weightand inertia would be seriously increased.

Having described the invention what I claim as new and desire to secureby Letters Patent is 1. Breech mechanism for firearms, comprising abreech block consisting of a main portion and a locking piece carriedthereby, said main portion and locking piece having cooperating partsinterlocked by a predetermined relative rotational movement of the mainportion and locking piece, and movable breech opening and closing meanscoacting with said locking piece and adapted to impart rotationallocking and unlocking movements thereto less in extent than theaforesaid predetermined movement, said locking piece when in lookingposition coacting with parts on the breech chamber.

2. Breech mechanism for firearms, comprising a breech block having areduced extension at the rear end thereof, a relatively short lockingpiece abutting against the rear face of said block and rotatable on saidex tension, said locking piece and block having integral coactinginterlocking means, and movable breech openingand closing meansco-acting with said locking piece to impart rotational locking andunlocking movements thereto, to cause the same to engage with anddisengage from locking parts on the breech chamber.

3. Breech mechanism for firearms, comprising a breech block consistingof a main portion and a locking piece carried thereby and provided witha projection, said main port-ion and locking piece having cooperatingparts interlocked by a predetermined relative rotational movement of themain portion and locking piece, and movable breech opening and closingmeans provided with cam means co-acting with the projec tion on thelocking piece to impart rotational locking and unlocking movementsthereto less in extent than the aforesaid predetermined movement, saidlocking piece when in looking position co-acting with parts on thebreech chamber.

4. Breech mechanism for firearms, comprising a breech block having areduced extension at the rear end thereof, a relatively short lockingpiece abutting against the rear face of said block and rotatable on saidextension and provided with a projection, said locking piece and blockhaving integral angularly spaced co-acting interlocking means, andmovable breech opening and closing means provided with cam meansco-acting with the projection on the locking piece to impart rotationallocking and unlocking movements thereto, to cause the same to engagewith and disengage from locking parts on the breech chamber.

5. Breech mechanism for firearms, comprising a breech block having areduced extension at the rear end thereof, a relatively short lockingpiece abutting against the rear face of said block and rotatable on saidextension, said extension and look ing piece having cooperating partsinterlocked by a predetermined relative rotation of the locking pieceand main portion, and movable breech opening and closing means co-actingwith said locking piece to impart rotational locking and unlockingmovements thereto less in extent than said predetermined movement, tocause the same to en gage with and disengage from locking parts on thebreech chamber.

6. Breech mechanism for firearms, comprising a breech block consistingof a main portion and a relatively short locking piece carried therebyand rotatable thereon and provided with a radial projection, saidlocking piece and block having integral align-- larly spaced co-actinginterlocking means, a gas operated piston, and a member directlyconnected to the rear end of said piston. said member having cam meansdirectly coacting with the projection on the locking piece to effectrotational locking and unlocking movements of said locking piecerelatively to locking parts on the breech cham her.

7. Breech mechanism for firearms, comprising a breech block, arelatively short locking piece of substantially the same diam eter assaid breech block and abutting against the rear face of said block,cooperating parts integral with said block and looking piece forconnecting the locking piece to the block to move axially therewith, andmovable breech opening and closing means co-acting with said lockingpiece to impart rotational locking and unlocking movements thereto tocause the same to engage with and disengage from locking parts on thebreech chamber.

8. Breech mechanism for fixed barrel automatic and semiautomaticfirearms, comprising a movable breech opening device operated by a gasimpulse from the muzzle end, a breech block consisting of a main portionand a relatively small and light nut or locking piece capable ofrotation relatively to the main portion of the breech block and carriedon its rear end, means carried upon said movable breech opening devicefor ro-" tating said nut or locking piece, locking and unlocking of thebreech block being effected by a rotational movement of the nut orlocking piece alone, and a firing pin in the breech block, the lirinppin and the nut or locking piece of the breech block having cooperatingprojections and recesses whereby the firing pin can only move forward tofire a cartridge when the nut or locking; piece is in properly lockedcondition.

9. Breech mechanism for anti'in'iatic and seiniailtomatic firearms.comprising a movable breech openimc derive and a brccrh block consistingof a mainportion and a relatively small and light nut or locking; piececapable of rotation relatively to the main portion of the breech blocl;and carried at the rear end thereof, said breech block parts havingrotationally engaging parts remaining in engagement after rotationaldisengagement of the locking piece from the breech and disengagcablefrom one another by a further relative rotation.

10. Breech mechanism for fixed barrel automatic and semi-automaticfirearms, comprising a movable breech opening device operated by a gasimpulse from the mosaic end and a breech block consisting of a mainportion and a relatively small and light not or locking piece capable ofrotation rein-- tively to the main portion of the breech block, and tothe fixed breech chamber, said parts cooperating to effect locking andunlocking of the breech block by a rotational movement of the nut orlooking piece alone by means carried upon the said movable breechopening device, and a firing pin in the breech block located in relationto the said nut or locking piece by a device held in place by assemblywith the breech block parts.

11. A breech block for a firearm, comprising a main portion and alocking piece rotatably carried thereby, said main portion and lockingpiece having coopij-rating parts interlocked by a prcdctermincd relativeangular movement of the main portion and locking piece less than acomplete rotation but greater in extent than the rotational locking andunlocking; movements oi. said locking piece, and said locking piece.having means for cooperating, with operating means.

12. A breech block for a firearm, comprisingg a main portion and arelatively short locking piece of substantially the same di amctcr assaid main portion abutting against the rear face thereof and rotatablerelatively thereto, said main portion and locking, piece havingangularly spared co operating parts integral therewith or connecting thelocking piccc to the main portion by a relative axial movement and arelative roiiitire movement to in erlock said parts.

13. A breech block for a firearm, comprising a main portion having: areduced extension at the rear end thereof and a rela tively shortlocking piece abutting against the rear face of said main portion androtataliile on said extension, said locking piece and extension havingintegral angularly spaced co-actinp, interlocking means interlocked byrelative rotative movement of greater extent than the locking andunlockinn movements of said locking piece, and said locking piece havingmeans for cooperating with operating 'means.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ISAAC NEWTON LEWIS.

W itnesses J. CUTLER, P. A. OUTHWARTE.

